High density combination dry hay and haylage/silage livestock feed-making appartus

ABSTRACT

A compression apparatus for compressing livestock feed comprises a hopper for receiving the feed; a precompression assembly precompressing the feed; a first compression chamber coupled to the hopper to receive the precompressed feed therefrom; a first ram movable along a longitudinal axis of the first compression chamber and having a first pusher plate for pushing the precompressed feed along the longitudinal axis of the first compression chamber to produce a compressed block of mixed feed product; and a second, reduced volume compression chamber operatively connected to the first compression chamber at a distal end of the first compression chamber for receiving compressed feed pushed from the first compression chamber by the first pusher plate. The first pusher plate defines one side of the second compression chamber when the first ram is fully extended and the second compression chamber has an opening at one end thereof for discharging the compressed feed. A second ram, movable along a longitudinal axis of the second compression chamber, has a second pusher plate for pushing the compressed blocked of mixed feed product along the longitudinal axis of the second compression chamber.

RELATED APPLICATION DATA

This application is a divisional application of U.S. Ser. No.08/250,796, filed May 27, 1994 now abandoned.

BACKGROUND OF THE INVENTION

The present invention pertains to the formulation, packaging andshipping of high density livestock feeds and more particularly to a highdensity livestock feed comprising fermented fodder, and a method andapparatus for packaging such feed for long distance shipping andhandling with minimal spoilage.

Conventionally, livestock fodders have been packaged and stored in anumber of different ways. One of the most common is in the form of hay,in which the fodder is cut and sun dried, and then is typically baled.Another common form of livestock feed is silage or haylage, in whichfeeds such as corn or alfalfa are cut, chopped and ensiloed in a highmoisture condition so as to ferment. Another form of livestock feed ispellets or cubes of fodder that have been finely chopped andextruded--this form is preserved, stored and shipped in a dry state.Each form of feed has its own advantages and disadvantages.

For long distance shipping, especially overseas, preservability andeconomical shipability of livestock feed are critical issues.Historically, only dry feeds--hay and cubes or pellets--have met bethcriteria. Pellets have a relatively high density, and preserveadequately as long as they are kept dry, but are expensive to produce.Baled hay is a somewhat less expensive form of feed, and stores andships well as long as it is kept dry, but hay is also less dense so itsrelative shipping cost it higher than for pellets. In the last decade,however, it has become common for hay bales to be doubled compressed toincrease shipping efficiencies. In particular, it has become commonplaceto ship double-compressed baled hay from the United States to foreigncountries that lack adequate feed production capacity, such as to Japan.

In order to be stored as hay, and even more importantly, for longdistance shipping, the hay must be thoroughly dried. Otherwise, the haycan mold, mildew, oxidize and spoil, and can heat and possibly evenignite due to spontaneous combustion. For transoceanic shipping inenclosed cargo containers, the hay should have a moisture content ofless than about 12%. Double compressed baled hay typically weighs in therange of 20 to 30 pounds per cubic foot.

Dried hay has several drawbacks. One drawback is that the curing processreduces the feed value of the hay, and the feed value continues todeteriorate gradually over time. Another drawback is that dry hay is notas palatable, nor as digestible, as fresh hay. Pellets and cubes are notany better in this regard.

Livestock fodders have also commonly been stored in the form of silage,such as chopped corn or sorghum, or haylage, which is wet chopped hay.For convenience hereinafter, this type of feed will be referred tocollectively as silage, except where haylage is specified. The storagemechanism for silage is entirely different from that of dried hay. Thefodder is ensiloed, that is, it is chopped and packed tightly into asilo or storage pit, plastic bag or other sealable container, and ispreserved by fermentation. Silage-type feeds must be stored with a veryhigh moisture content, over 40% and preferably around 60% water.Fermenting the chopped, wet fodder in an essentially air-freeenvironment forms acids and alcohol which aid in preserving the silage.

Silage has several advantages over dry hay. First, the silage method ofpreserving the feed maintains a very high proportion of the initialnutrient value of the feed. Moreover, the ensiloed feed maintains a highnutrient content for a long period of time. Second, the silage is verypalatable and very digestible by livestock. Because it is moist andtender, cattle can chew silage or haylage easily; the feed is verytasty; and it can be digested easily by cattle. Silage-type fodders are,therefore, a very desirable livestock feed, particularly for dairy andfeedlot herds.

Silage-type feeds suffer, however, from two main disadvantages. Onedisadvantage is that, containing a very high percentage of water, suchfeeds are very heavy as well as bulky, and therefore uneconomical totransport over any significant distance. The other main disadvantage isthat silage can spoil within a matter of hours when exposed to the air.

Some livestock feeders have tried blending silage or haylage with dryhay to improve the quality of the feed. Because the silage can quicklyspoil, however, such blending is generally done where the blended feedproduct is to be consumed.

Heretofore, no techniques have been known for packaging and preservingsilage-type feeds for economical shipment. The usual techniques thathave been developed for preserving and packaging food stuffs, such asfreezing, canning and vacuum packaging, are used for packaging the foodstuffs in small quantities. They do not appear to be practical and arenot known to applicants to have not been used for storing or shippinglarge bulk quantities of fermented livestock feeds.

One company, AgBag Corporation, has developed a system for ensiloinglivestock feed in an elongated plastic bag as described in U.S. Pat.Nos. 4,424,051; 4,337,805; 4,310,036 and 4,308,901. The AgBag systemappears to be limited to use on the farm, due to the large size, bulkand weight of the silage-filled storage bags, and not economical forlong distance shipping. Also, due to the large size and bulk of thefilled silage bags, it appears that handling of such containers withoutdamage would be difficult. Also, it is unlikely that unloading machinerycapable of handling such packages would be available at foreign ports.

As a result, notwithstanding the significant advantages of silage-typefeeds over dried hay pellets and cubes, all transoceanic experts oflivestock feeds known to applicants have been in the form of single ordouble compressed dry hay bales, or in the form of extruded, essentiallydry pellets or cubes of hay or silage.

Accordingly, a need remains for a way to package and ship livestock feedwhich has more of the advantages of beth baled hay and silage and fewerof the disadvantages of each type of livestock feed.

SUMMARY OF THE INVENTION

One object of the invention, therefore, is to maximize the advantages ofprior methods of feed storage and handling while minimizing thedisadvantages.

Another object of the invention is to enable economical packaging andshipment of a more nutritious digestible form of livestock feed.

A further object is to enable a livestock feed comprising fermentedsilage to be packaged and preserved in a high density form suitable forlong distance shipping without spoilage.

One aspect of the invention is a livestock cargo unit comprising a blendof dry hay or other fodder and moist haylage or silage intimately mixedtogether and highly compacted into a watertight bag. The blended dryfodder and haylage/silage feed product is mixed in a ratio that producesa net moisture in the range of 20%-35%, preferably within the range of25%-30% and ideally at about 30% net moisture. This is approximately twoand half times the moisture content of dry hay and about half of theusual moisture content of silage. The ratio of components in the blendedfeed product is preferably 62% by weight of typical dry fodder, such asdry baled hay of about 12% moisture, and 38% by weight of haylage orsilage having a typical moisture content of about 60%, but preciseproportions can be varied to control the net moisture percentage of theblended feed product. Optionally, vitamins minerals or other nutrientscan be added to the blended dry fodder and haylage or silage.

The blended feed product is compressed into fixed volume units, whichare packaged in durable airtight bags at a density of approximately 40pounds per cubic foot. For ease of handling, a preferred size of bag isabout 2.5 cubic feet, which contains about 100 pounds of blended feedproduct. The filled bag is preferably airtight, and is evacuated toremove as much oxygen as possible and thereby avoid oxidation of thefeed. The vacuum should be a minimum of 10 inches of mercury, anddesirably at least 20 inches of mercury and preferably 25 inches ofmercury.

Alternatively, any oxygen remaining in the bag at the time of closurecan be displaced by flashing back with a suitable inert gas, such as CO₂or N₂, or a mixture of inert gases. A further alternative is to use agas permeable bag to contain the compressed blend of forage materialsand to stack a plurality of the filled closed bags in a larger airtightshipping container. The entire container is preferably evacuated but canalso have the oxygen displaced therefrom by an inert gas.

A second aspect of the invention is a method for making the foregoingfeed product. In the first step, dry fodder, typically previously-baledhay, having a moisture content of about 8% up to about 15%, is mixedwith silage (and/or haylage) containing 40%-70% moisture in a ratioproportioned to produce a net moisture content in the mixed feed productthat is the range of 20%-35%, preferably about 30%. The preferredproportions, for hay at 12% moisture and silage at 60% moisture, is 62%dry fodder to 38% silage. These components are mixed for a sufficienttime to distribute the moisture content of the silage uniformlythroughout the blended mixture. In production quantities in a batchprocess, this mixing requires a residence time in the mixer in the rangeof 10 to 20 minutes, typically about 15 minutes.

The feed mixture is then metered to a compression apparatus, which ispreferably designed to provide a multi-stage compaction of the feedmixture. The feed mixture is input at a density of approximately 16.6pounds per cubic foot. A first stage compression step, performed usingeither a gravity/auger system or a pre-compression ram, densities thefeed product to a uniform density, e.g., about 25 pounds per cubic foot.A second compression stage, preferably implemented by means of a firsthydraulic compression ram, further compresses a predetermined firstvolume of the uniform density feed mixture to a reduced, second volume.A third compaction stage uses a second hydraulic compression ramoriented at a right angle to the second stage ram, ejects and pressesthe blended highly compressed, feed product from the compressor.Preferably the feed is ejected at a density of about 40 pounds per cubicfoot into a durable watertight and preferably airtight bag, therebyfilling the bag with blended compressed hay/silage a density of about 40pounds per cubic foot. The filled bag is then vacuumed sealed,discharged and stacked.

A further aspect of the invention is an apparatus for implementing theforegoing method. The apparatus comprises a mixer having two inputs, onefor dry hay and the other for silage or haylage. The mixer is preferablya batch-type mixer having an output which discharges to a meter box thatlevels the flow of mixed feed product and relays the feed product to acompressing apparatus. The mixer can include a scale for weighing thematerial as it is blended in the mixer. The compressing apparatus canalso include a scale. Controls responsive to these scales can be used tocontrol the flow rate of material through the system, as well as thefinal weight of the bagged feed product. The inputs to the mixer arepreferably in the form of a pair of floor drag conveyor portions. One ofthese portions, that used for inputting haylage or silage, can includean extruder to reduce the moisture content of the input haylage orsilage. The compression apparatus preferably includes means forcompressing the blended feed product in three stages. The first stageincludes either a gravity feed auger system, or a pre-compression ram,which receives the blended feed product from the metro box and feeds itinto a first hydraulic ram compression chamber. The first stagestructure is designed and operated primarily to densify the blended feedproduct to a predetermined uniform density. The first chamber includes afirst hydraulic compression ram that is oriented to operate in ahorizontal direction to compress a fixed volume of the feed productinput from first stage structure into a reduced volume in a second ramcompression chamber. The second compression chamber and includes ahydraulic ram oriented horizontally at a right angle to the firsthydraulic ram. In this section the compressed feed is moved laterally ofthe first ram to be ejected into a bagging apparatus. The baggingapparatus includes a bag closure mechanism and evacuation apparatus forevacuating the bag as it is being sealed.

The invention solves a number of problems in the prior art. It providesa very palatable, digestible and nutritious blended feed product. Thehaylage or silage moistens the dry fodder to make it more palatable anddigestible, and contributes a high nutrient value to the blendedproduct. The dry fodder reduces the moisture content of the overallblend of feed product, and increases the overall net feed content on aper gross ton basis well above that provided by conventional haylage orsilage. At 40 pounds per cubic foot and 30% moisture content, the totaldry matter content per cubic foot rivals that of the dense, doublecompressed hay (typically 22 pounds per cubic foot and 12% moisturecontent), making it economical to ship as well as a more desirable feedproduct. Packaging the blended feed product in a highly compactedcondition, with a relatively high moisture content contributed by thesilage, and little, if any, residual oxygen, minimizes oxidation andavoids spoilage and heating of the feed product.

An important advantage of the invention is that it retains a relativelylong-fiber length in the feed product. In contrast, cubing dry hayreduces the fiber length of the hay to under 4 inches.

The foregoing and other objects, features and advantages of theinvention will become more readily apparent from the following detaileddescription of a preferred embodiment of the invention which proceedswith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a system for blending, compacting andpackaging dry hay and silage in accordance with the invention.

FIG. 2 is an elevation view taken along lines 2--2 in FIG. 1.

FIG. 3A is a side elevation view of the mixer 22, with interior augerdetails shown in dashed lines.

FIG. 3B is an end elevation view of the mixer of FIG. 3A, showing theaxial arrangement of the augers in dashed lines.

FIG. 3C is a perspective view of the mixing chamber of FIG. 3A.

FIG. 3D are side elevation views of the different augers shown in themixer of FIGS. 3A and 3B.

FIG. 4A is a top plan view of the press bagger of the system of FIG. 1and FIGS. 4B-4D show progressive stages of operation of the pressbagger.

FIG. 5 is a cross-sectional view taken along lines 5--5 in FIG. 4A.

FIG. 6 is a flow diagram of the process for blending, compacting andpackaging dry hay and silage in accordance with the invention.

FIG. 7 is a flow diagram of an alternative embodiment of the process forblending, compacting and packaging dry hay and silage.

FIG. 8 is a top plan view of an alternative embodiment of compressionapparatus according to the invention.

FIG. 9 is a side elevation view of the compression apparatus of FIG. 8.

FIG. 10 is an end elevation view of the compression apparatus of FIG. 8.

FIG. 11 is a perspective view of the compression chamber structure usedin the compression apparatus of FIGS. 8-10.

FIGS. 12A-12C are a series of perspective views similar to FIG. 11 witha portion of the side walls broken away to show interior structure,illustrating steps in the operation of the compression apparatus.

FIG. 13 is an exploded perspective view of the compression chamber firstgate.

FIG. 14 is a schematic of hydraulic circuitry for actuation of the gatecylinders and press cylinders in the compression apparatus of FIGS.8-13.

FIG. 15 is a side elevation view of the compression apparatus of FIG. 8mounted on a stand in position to discharge blocks of high densitycompressed hay/silage feed product into a multistation bagger inaccordance with the invention.

FIG. 16 is an end elevation view of the bagging apparatus of FIG. 15.FIG. 17 is a top plan view of the bagging apparatus of FIG. 16.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a preferred embodiment of a system 10 of apparatusfor implementing the invention. The system 10 comprises hay/silageinfeed and mixing apparatus 12, blended hay/silage flow levelingapparatus 14, and compression apparatus 16, together withinterconnecting conveyors.

The mixing apparatus 12 comprises a mixer 20 having two input conveyors,a first conveyor 22 for infeeding dry hay and a second conveyor 24 forinfeeding silage or haylage. Optionally, the second conveyor includes anextruder 26 for reducing the liquid content of the input silage beforeblending. The input conveyors 22, 24 are conventional horizontal floordrag-type conveyors. The illustrated mixer is a batch-type mixersupported on a scale 21 for weighing the input proportions of dry hayand silage as the mixer is filled. Alternatively, the mixer can be acontinuous-type mixer and the input proportions of dry hay and silagecan be metered by metering apparatus associated with the inputconveyors.

The preferred form of the mixer 20 is shown in FIGS. 3A-3D. The mixerincludes a mixing chamber 70, better seen in FIG. 3C, having an opentop, inwardly tapered sidewalls 72, 74 and parallel endwalls 76, 78. Adrive housing 80 is mounted on one endwall. Two upper augers 82, 84 andtwo lower augers 86, 88 are journaled in the opposite endwalls 76, 78.The augers are driven by a drive assembly (not shown) in housing 80. Theupper augers 82, 84 are spaced along upper portions of sidewalls 72, 74,respectively, and the lower augers 86, 88 are spaced close together atthe bottom of mixing chamber 70. The augers are arranged as shown inFIG. 3D to accommodate the introduction of dry hay and silage from theinfeed conveyors and to output mixed feed product from the dischargeconveyor.

The mixer 20 has an output which discharges via a first transferconveyor 28 to leveling apparatus 14 which includes a meter box 30. Thetransfer conveyor 28 is angled upward to discharge the blended feedproduct into the meter box 30 from above. The meter box 30 meters theblended feed product out to a second transfer conveyor 32. The secondtransfer conveyor includes a leveler 34 which levels the flow of mixedfeed product before relaying the feed product to the compaction andbagging apparatus 16. The second transfer conveyor is otherwise similarto the first transfer conveyor.

The compression apparatus 16 receives the blended feed product andcompresses it into a high density block which is then ejected to abagging apparatus (not shown). The compression apparatus preferablyincludes apparatus for compressing the blended feed product in threestages, as shown in FIGS. 4A-4D. The first or precompression stageincludes a gravity feed hopper 40 which receives the blended feedproduct discharged from the second transfer conveyor and a verticalauger system. The vertical auger system includes a pair of augers 42positioned along one side of the hopper, providing a receiving space 44for the blended feed product. The receiving space 44 has a widthapproximately equal to the diameter of the augers. The augers 42 rotateabout parallel vertical axes to feed the hay/silage blend downward intoa first hydraulic ram compression chamber 48.

The first compression chamber 48 includes a first hydraulic ram 50 thatis oriented to operate in a horizontal direction. Mounted on anactuation rod 51 of ram 50 is a pusher plate 52. The chamber 48 andpusher plate 52 have a rectangular cross-sectional shape. When the ramis extended as shown in FIG. 4B, the pusher plate 52 sweeps the feedproduct laterally from beneath the augers 42 into a second, reducedvolume compression chamber 54. This action further compresses theblended feed product. The pusher plate includes a top shield plate 53extending rearward in chamber 48 to keep the augers from feeding morefeed down behind the pusher plate when ram 50 is extended.

The second compression chamber 54 leads to the vestibule (not shown). Asecond hydraulic ram 56 is mounted at one end of chamber 54, orientedhorizontally at a right angle to the first hydraulic ram.

This chamber is also rectangular and is swept by a rectangular or squarepusher plate 58 mounted on the actuation rod 57 of ram 56. When ram 56is extended, as shown in FIG. 4C, the compressed feed is moved laterallyof the first ram into a bagging chamber 60, further described below.Pusher plate 52 serves to enclose one side of chamber 54 during thiscompression stage, until the pusher plate 58 is retracted, as shown inFIG. 4D. Then pusher plate 52 is retracted.

The bagging chamber 60 includes a gate mechanism 62 and sealing andevacuation apparatus 64 for evacuating the bag as it is being sealed.

The gate mechanism includes a pair of ram-actuated sliding gates 66, 68which, when closed, form a sidewall of chamber 48 and an endwall ofchamber 54. These gates are opened to permit the compressed feed productto be ejected via bagging chamber 60.

The compressor 16 can include a scale (not shown) and controlsresponsive to these scales, for controlling the flow rate of materialthrough the system, as well as the final weight of the bagged feedproduct. These controls also sequence the compression and bagging stepsdescribed above. An example of the hydraulics control circuitry is shownin FIG. 14.

FIG. 6 is a flow diagram of the blending, compression and baggingprocess implemented in the above-described apparatus for making theblended hay/silage feed product of the invention. In a first step 110,dry fodder, typically previously-baled hay, is mixed with silage (and/orhaylage) in a ratio proportioned to produce a net moisture content inthe mixed feed product that is the range of 20%-35%, preferably under30% and more preferably about 25%. The moisture content of the input dryhay can be about 8% up to about 15% and the input silage can contain40%-70% moisture. Preferably, the moisture content of the hay is about12%, and that of the silage about 60%. At these preferred moisturecontents, the mixing ratio 62% dry fodder to 38% silage will yield amixed feed moisture of about 30%. These components are mixed for asufficient time to distribute the moisture content of the silageuniformly throughout the blended mixture. In production quantities, thisrequires a residence time in the mixer in the range of 10 to 20 minutes,typically about 15 minutes.

The feed mixture is then metered into a compression apparatus. Themetering step 112 includes a volumetrically constant metering of theblended feed product, which can be gated by a weight measurementindicated at step 114. A scale measures the weight of feed product as itaccumulates in the compression apparatus, and turns off the infeed oncea predetermined weight is achieved, e.g., about 100 pounds (45 kg.).

The compression apparatus is preferably designed to provide amulti-stage compaction of the feed mixture, as described above and asindicated in FIG. 6 by steps 116, 118, 120, but is not so limited inthis process. The blended hay/silage feed mixture is input to thecompression apparatus at a density of approximately 16.6 pounds percubic foot and compressed to a density of 30-45 pounds per cubic foot,preferably about 40 pounds per cubic foot.

In the last stage of compression, shown as step 120, the compressed feedproduct is compacted into a watertight bag. In the preferred embodimentof the process shown in FIG. 6, this bag is also airtight. The filledbag is vacuum sealed in step 122, and then discharged and stacked insteps 124 and 126.

The filled airtight bag is evacuated in step 122 to remove as muchoxygen as possible and thereby avoid oxidation of the feed. The vacuumshould be a minimum of 10 inches of mercury, desirably at least 20inches of mercury, and preferably 25 inches of mercury. Alternatively,any oxygen remaining in the bag at the time of closure can be displacedby flashing back with a suitable inert gas, such as CO₂ or N₂, or amixture of inert gases.

Referring to FIG. 7, steps 110 through 120 are identical to the samesteps in FIG. 6, except that an airtight bag is not used and is notevacuated before sealing. This alternative embodiment uses a gaspermeable bag to contain the compressed blend of forage materials. Afterfilling, the bag is closed (step 130) and a plurality of the filledclosed bags are stacked in a larger airtight shipping container (step132). The entire container is preferably evacuated in step 134 but,alternatively, the oxygen can be displaced therefrom by an inert gas.

FIGS. 8-10 show a second embodiment of the compression apparatus. Inthis embodiment, the compression apparatus 116 resembles apparatus 16 inthat it is arranged to compress the blended feed product in threestages. Rather than a gravity feed hopper and vertical pair of augers,this embodiment uses a small surge bin 140, which holds the material insufficient amount to always fill a charging chamber 142 positionedbeneath the end 140, at each stroke of a precompression ram 144. Theprecompression ram is oriented to operate in a horizontal direction.Mounted on its actuation rod is a pusher plate (not shown) similar topusher plate 52, previously described. When the ram retracts, blendedfeed product drops into the charging chamber, and then ram 144 pushesthe feed product forward. The ram pushes the feed product through anopen injection gate 146, operable by actuation of ram 148, intocompression chamber 150. Compression chamber 150 is collinear with thecharging chamber 142 and has a main compression ram 152 mounted inopposition to precompression ram 144. During operation of precompressionram to insert the material into the compression chamber 150, thecompression ram 152 pushes the material toward the main compression ramuntil it abuts against a pusher plate (not shown) on the maincompression ram. The hydraulic circuit 166 (FIG. 14) to theprecompression ram includes a pressure sensor for detecting the backpressure of the blended feed product in chamber 150. At a set pressure,the precompression ram steps. This assures that a uniform density isattained in the material precompressed in the chamber 150 during eachcycle. If the precompression ram reaches the end of its travel, asdetermined by a position sensor, without the predetermined pressurebeing exceeded, the control circuitry will automatically retract to theram to admit more material from the surge bin and then push theadditional material toward chamber 150 until the predetermined pressureis attained. This step in the operation of compressor 116 is illustratedin FIG. 12A.

Once the preset pressure on the precompression ram control is attained,the injection gate 146 is closed by operation of ram 148. This step isshown in FIG. 12B. As shown in FIG. 13, gate 146 includes a windowportion 147, through which the material is pushed from theprecompression chamber 142 into compression chamber 150, and a solid, orblocking portion 148, which separates the two chambers when gate 146 isclosed. Gate 146 also includes a pair of knives 149, spaced on oppositesides thereof, for shearing off the feed product as the gate 146 isclosed. When the injection gate 148 closes, it seals the compressionchamber opposite the main compression ram 142. The compression ram thenpresses the feed product toward the injection gate, substantiallyreducing its volume and increasing its density to about 40 pounds percubic foot. The main compression ram preferably overcompresses thematerial slightly, pushing its pusher plate about 1/2" past the insidewalls of dwell chamber 160 and then backing off to a position flush withthe dwell chamber wall. In this position, the pusher plate forms aportion of the sidewall of the chamber through which ejection ram 156operates. For actuation of the ejection ram, an ejection gate 162,actuated by a pair of rams 164, is opened to connect the compressionchamber to dwell chamber 160. In this third stage, the compressed blockof feed products remains through the dwell chamber for the entirety ofthe next succeeding cycle to allow the compressed feed product to losesome of its resilience. As the new block enters the dwell chamber, theblock from the preceding cycle is forced out of the dwell chamber to abagging apparatus.

The extremely high pressures exerted in the above-described compressionapparatus subject the hydraulic rams to extreme stress. To withstandthese stresses, applicant preferably uses heavy duty (HH Series) Shefferrams with custom cylinder heads, extended cushions, and high strengthtie rods, and a unitary piston/rod. Position sensors are used in allrams to control deceleration of the rod at the end of each stroke. Adigital controller connected to receive signals from these sensorsdetects the location and rate of acceleration of the rod to dynamicallyadjust to varying condition, including temperature, related viscositychanges and hydraulic oil.

The compression chamber structure must similarly withstand highstresses. The presently preferred structure of the compression chambersis shown in FIG. 11.

FIG. 14 shows the hydraulic circuitry 166 for the compressor 116.Operation of each of the gate and compression rams is controlled by athree-way valve 168, 169, operation of which is in turn controlled by adigital controller programmed to sequence the above-described operationas well as to control the individual operation of each of the rams inresponse to position and pressure sensor signals received duringoperation.

FIG. 15 shows a variation of compression apparatus 116A, in which theejection ram 156 and dwell chamber 160 are oriented vertically. Thebagging apparatus operates on the principle of a carousel-type device.It can be oriented to operate on a vertical axis, as shown in FIGS.15-16, or can be rotated to operate on a horizontal axis to accommodatea horizontal discharge of the blocks of feed product as in the apparatusof FIG. 8.

Referring to FIG. 17, the bagger includes a bag placing station A, aproduct receiving station B, and a vacuum pack and sealing station C.

At station A, a bag is placed on the rotating platform. Once theplatform has been rotated, internal and external bagging sleeves 182,184 position the bag in station B, the block of compressed feed productis inserted by bagging ram 186 into the bag. Continuing to station C, avacuum pump 176 evacuates the bag and a bag sealer 178 seals it toexclude substantially all oxygen from further contact with the block ofcompressed blended feed. At the last station the bagged feed product isreleased onto a conveyor 180 for movement to another location forcontainerization.

Having described and illustrated the principles of the invention in apreferred embodiment thereof, it should be apparent that the inventioncan be modified in arrangement and detail without departing from suchprinciples. We claim all modifications and variation coming within thespirit and scope of the following claims.

We claim:
 1. A compression apparatus for compressing livestock feedcomprising:a hopper for receiving the feed; means for precompressing thefeed; a first compression chamber coupled to the hopper to receive theprecompressed feed therefrom; gate shearing means interposed between thefirst compression chamber and the precompression means; a first rammovable along a longitudinal axis of the first compression chamber andhaving a first pusher plate for pushing the precompressed feed along thelongitudinal axis of the first compression chamber to produce acompressed block of mixed feed product; a second, reduced volumecompressed chamber operatively connected to the first compressionchamber at a distal end of the first compression chamber for receivingcompressed feed pushed from the first compression chamber by the firstpusher plate, wherein the first pusher plate defines one side of thesecond compression chamber when the first ram is fully extended, thesecond compression chamber having an opening at one end thereof fordischarging the compressed feed; and a second ram movable along alongitudinal axis of the second compression chamber, the second ramhaving a second pusher plate for pushing the compressed blocked of mixedfeed product along the longitudinal axis of the second compressionchamber.